HLA-DQ1 is a
serotype that covers a broad range of
HLA-DQ
HLA-DQ (DQ) is a cell surface receptor protein found on antigen-presenting cells. It is an αβ heterodimer of type MHC class II. The α and β chains are encoded by two loci, HLA-DQA1 and HLA-DQB1, that are adjacent to each other on chromos ...
haplotype
A haplotype ( haploid genotype) is a group of alleles in an organism that are inherited together from a single parent.
Many organisms contain genetic material ( DNA) which is inherited from two parents. Normally these organisms have their DNA or ...
s. Historically it was identified as a DR-like alpha chain called DC1;
later, it was among 3 types DQw1 (later DQ1, and split into
DQ5 and
DQ6), DQw2 and DQw3. Of these three serotyping specificities only DQw1 recognized DQ alpha chain.
The serotype is positive in individuals who bear the DQA1*01 alleles. The most frequently found within this group are: DQA1*0101, *0102, *0103, and *0104.
In the illustration on the right, DQ1 serotyping antibodies recognizes the DQ α (magenta), where antibodies to DQA1* gene products bind variable regions close to the peptide binding pocket.
Serotypes
The serotyping efficiency of DQ1 recognition relative to DQ5 and DQ6 is listed below. Since DQ1 recognizes alpha, the DQ5 and DQ6 recognition are to beta chain. Meaning that DQ1 is corecognized with DQ5 and DQ6.
The table to the left shows some of the serotyping efficiencies.
Efficient recognition of a genotyped allele approaches 100%.
Compared to DQ2 serotyping of DQB1*0201 positive individuals (98%), the efficiency of DQ1 recognition is relatively low and error prone.
For this reason DQ1 serotyping is a poor method of typing for transplantation or disease association prediction or study.
Nonetheless, it is still widely used and association purported in the literature.
Alleles
DQA1*0101
DQA1*0101 is commonly linked to haplotypes of DQB1*05, the common DQA1*0101:DQB1*0501
haplotype which is part of a broader DR1-DQ1 haplotype.
DQA1*0102
DQA1*0102 is associated with both DR5 and DR6.
DQA1*0102:DQB1*0502 has a bimodal distribution. It is found in the Philippines in high frequency and on the Mediterranean island of
Sardinia
Sardinia ( ; it, Sardegna, label=Italian, Corsican and Tabarchino ; sc, Sardigna , sdc, Sardhigna; french: Sardaigne; sdn, Saldigna; ca, Sardenya, label=Algherese and Catalan) is the second-largest island in the Mediterranean Sea, after ...
.
DQA1*0102:DQB1*0602 is a very common haplotype in Eurasia, with higher frequency in central Asia relative to elsewhere. It is part of a European ancestral haplotype B7-DR15-DQ1 that appears to have expanded asymmetrically into Europe. The A3-B7-DR15-DQ1 haplotype indicates relationships in Eurasia that span from Korea to Ireland, indicating some common
ancestry in recent times.
DQA1*0102:DQB1*0604 much less frequently found but spread widely.
DQA1*0103
DQA1*0103 (*0103) shows a negative (protective) association with many autoimmune disease, this association is apparent in Japanese studies in the *0103:DQB1*0601 haplotype, and in Europe with the *0103:DQB1*0603 haplotype, indicating the protective effect is influenced by the alpha chain of DQ. DQA1*0103 is protective against
Behçet's disease
Behçet's disease (BD) is a type of inflammatory disorder which affects multiple parts of the body. The most common symptoms include painful sores on the mucous membranes of the mouth and other parts of the body, inflammation of parts of the e ...
,
,
juvenile diabetes
Type 1 diabetes (T1D), formerly known as juvenile diabetes, is an autoimmune disease that originates when cells that make insulin (beta cells) are destroyed by the immune system. Insulin is a hormone required for the cells to use blood sugar f ...
,
steroid-sensitive
nephrotic syndrome,
[,]
coeliac disease
Coeliac disease (British English) or celiac disease (American English) is a long-term autoimmune disorder, primarily affecting the small intestine, where individuals develop intolerance to gluten, present in foods such as wheat, rye and barle ...
multiple sclerosis
Multiple (cerebral) sclerosis (MS), also known as encephalomyelitis disseminata or disseminated sclerosis, is the most common demyelinating disease, in which the insulating covers of nerve cells in the brain and spinal cord are damaged. This d ...
,
chronic active
hepatitis C
Hepatitis C is an infectious disease caused by the hepatitis C virus (HCV) that primarily affects the liver; it is a type of viral hepatitis. During the initial infection people often have mild or no symptoms. Occasionally a fever, dark urine, a ...
,
and
Vogt–Koyanagi–Harada syndrome.
However, it may predispose carriers to chronic infection such as
leprosy
Leprosy, also known as Hansen's disease (HD), is a long-term infection by the bacteria ''Mycobacterium leprae'' or ''Mycobacterium lepromatosis''. Infection can lead to damage of the nerves, respiratory tract, skin, and eyes. This nerve damag ...
,
,
and
AIDS
Human immunodeficiency virus infection and acquired immunodeficiency syndrome (HIV/AIDS) is a spectrum of conditions caused by infection with the human immunodeficiency virus (HIV), a retrovirus. Following initial infection an individual m ...
.
DQA1*0103:DQB1*0601 is part of a multigene haplotype (DRB1*1502:DRB5*0102:DQA1*0103:DQB1*0601:DPA1*02:DPB1*0901) linked to
Takayasu's arteritis
Takayasu's arteritis (TA), also known as aortic arch syndrome, nonspecific aortoarteritis, and pulseless disease, is a form of large vessel granulomatous vasculitisAmerican College of Physicians (ACP). Medical Knowledge Self-Assessment Program (MK ...
in Japanese.
Another haplotype, DR8-DQ1 which contains this haplotype may be associated with
primary biliary cirrhosis,
Graves' disease
Graves' disease (german: Morbus Basedow), also known as toxic diffuse goiter, is an autoimmune disease that affects the thyroid. It frequently results in and is the most common cause of hyperthyroidism. It also often results in an enlarged thyr ...
There is a negative association of this DR15-DQ1 haplotype in Japanese with
inflammatory bowel disease.
DQA1*0103:DQB1*0603 is part of a DR-DQ haplotype (DR13-DQ1) that increases for primary sclerosing cholangitis
The same haplotype shows a negative association with rheumatic heart disease,
DQA1*0104
DQA1*0104:DQB1*0503 is part of a multigene haplotype DR14-DQ5 that is associated with MuSK positive Myasthenia gravis.
References
{{DEFAULTSORT:Hla-Dq1
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